Expression mechanism for mechanical musical instruments



' 1, Oct. 18,1927. ETOWER 646001,

EXPRESSION MECHAI IISM FOR MECHANICAL MUSICAL INSTRUMENTS- Filed March5, 1926 '2 Sheets-Sheet 1 VENT R. WITNESSES; m 0

0 t. 18,192. c 7 H. E TOWER EXPRESSION MECHANISM FOR MECHANICAL MUSICALINSTRUMENTS Fil'ed March 3. 1926 2 Sheets-Sheet 2 rr==m Patented Oct.18, 1927.

UNITED STATES PATENT. OFFICE.

unnsonnnnmownn, or- CINCINNATI, onrqnssreuon TO THE BALnWINcoMPANY,

onoINoINNA'rI, OHIO. V v p r Y nxrnnss on mncniANIsM 'Fo'a MECHANICALMusician ms'rnunnivcrs.

" Application filed March 3, 1926; Serial No. 91,982.

The expression mechanism for controlling the degree of tension in thechests of player actions that are used for operating the notes of apiano have been made ofvarious kinds,

but have allbeen so complicated and "hard to regulate that theordinaryrepair manor regulator could not regulate them. The

"present invention is made so simple that any onecanregulate it to givethe proper degrees of control and it 1s also made to'change the degreesso quickly and with such a short motion of the governor spring thattherewill be no wear and no lessenlng of the tenslon of this spring byconstant stretching.

A further object of my invention 1s to have a mufiier that will allowthe air to be drawn the .player action To create a partial vacuum in theplayer into the chests to reduce the tension and yet be quiet and willnot be clogged With dust from long usage.

In the drawings Figure 1 1s a "front view of a mechanical musicalnstrument showmg the pump, electric motor, expression mechanism and theplayer action. Flgure 2 1s a top view of the expression mechanism withthe muffler removed. Figure 3 is a top view of the mufller showing howit is slit to break up the air currents. Figure 4 is an end view of theexpression set showing how the muffler is held in place. Figure 5is across section takenalong line A-A ofFigure 2.

A player action 1 has a roll box 2 with a trackerbar 3 for controllingthe action of the pneumatics 4 as the music'roll 5 forward by theairmotor 6. Besides the regular note holes 7 in thertracker bar 3 there area number of expression control holesS, 9, 10 and ll'for controlling theac tion of a number of pneumatics12, 13, 14- and a pneumatic pouch-15,whichvact on areverse lever 16 that controls the action of a spring 17whichis connected to a valve rod 18 that carries a valve 19, which valve19 1s used to control the degree of a1r tension in action 1 foractuating the pneumatics 4, and

in the air motor 6 that drives the music roll 5, a pneumatic pump 20 isdriven by an electric motor 21 at such speed as to give the maximumtension needed. The pneumatic pump 20 is connected to the player actlon1 by a service hose 22, and to the control box 23 by a hose 24. It isalso connected to the air motor 6 by a suitable hose whlch is not shown.

is drawn I The pneumatics'12, 13,14 onflthecontrol box 23 are eachcontrolled by separate valves 25, 26, and'pouches-28, 29 and 30. Thepneumat1c pouch 15 is controlledxby a valve 31' and a pouch 32. Thesepneumatics 12, 13, 14 are adapted to press down on thereverse lever 16by means of arms 33, 3-4 and 35, whereas the pneumatic pouch l5act's-directly on thevalverod 18 from below and closes the valve 19. i

vings 3810f different size that act insidelofwa felt lining 39 in theport hole 37' to breakup the currents of air" that go through the porthole 37 to reduce the air tension in the player action. To furtherreduce the'noise ofthe arr passing through the port hole 37 a cover4051s made to fit over all the neumatics-and the control valve 19. Thiscover 40 is made with a plurality of long narrow slots'52 in the topthatact to break up the aircurrents vandit'is also covered withzaheavy'layer of felt 41. For easyaccess to the regulating controls thiscover is held in placeby .a' pair of latches 42 that hook over pinsprovided on the ends of the cover. j

To control the action ofthe pneumatics' 12, 13, and .14 on the reverselever 16, a number of-stop screws'43, 44 and 45 are set in the movableleaves of these pneumatics to limit the length of the stroke. Spring'l?is 's'et into the reverselever andheld in place by a p1n46, which pln-isalso used for regulating the tension of the spring-17.

The control holes, 8, 9, 10, 11 in the tracker bar 3 are connected tothe pouches 28, 29,30 and 32 by means of tubes 47, 48, 49 and 50 and thevalve 31 is connected to the pneumatic pouch 15 by a tube 51. i

When the electric motor 21 is started, it.

drives the pneumatic pump 20 causing a partial vacuum in the playeraction 1, control box 23 and air motor 6. If this pneumatic pump isoperated fast enough to cause a vacuum of 40 inches water gauge, thenotes will operate to bring out a very loud tone in the musicalinstrument. gree of vacuum the control valve 19 is set inside the vacuumchamber of the control To vary this deboxi23 and covers the port hole37. The effect of this vacuum is to pull the control valve 19 away fromthe port hole 37 allow ng atmospheric air to leak in until the tensionof the air in the control box 23 and the player action 1 is balancedwith the tension of the spring 17.

To be able to raise the tension of the air from the minimum governed bythe spring 17,1the pneumatics 12, 13, and 14: are set to ull down on thereverse lever 16, thereby 7 increasing the tension'of the spring 17 andraising the tension of the air inside the player action 1 and controlbox 23. The minimum tension is set by the balancing of vthe spring 17and the valve 19, at about 6 inches water gauge. lVhen an-opening in themusic roll5 uncovers the hole 8 in the tracker bar 3 the air is allowedto go through the tube 47 and operate the pouch 28, which 7 I will thenoperate the valve 25, causing the pneumatic 12 to collapseuntil theregulating screw 43 has touched the bottom board of the pneumatic. Thisregulating screw 43 is set so that when'the arm 33 presses the reverselever 16 down the spring 17 will be stiffened enough to raise thetension to 9 inches water gauge. WVhen the control opening 9 isuncovered, the air operates through the tube 48, pouch 29 and valve 26to collapse the pneumatic 13 to cause the block 3 1 to press down thereverse lever 16 until the regulating screw 14: strikes. is setv so;that the lever can be pulled down to give a tension of 12 inches Watergauge.

The action of the Pneumatic 14: is controlled in the'same manner throughopening 10, tube 49,pouch 30 and valve 27. The regulating screw is setso that the reverse lever 16 stiifens the spring 17 to give a tension of15 water gauge.

When the control opening 11 is uncovered :the' air-is admitted throughtube to pouch 32 that opens valve 31, admitting air through tube 51, tothe pneumatic pouch '15, which pouch 15 will be drawn up by thevacuuminsidelthe control box 23 and presson the valve rod 18'pressing thevalve 19 against the seat around the port hole 37.

When this valve 19 is tight against the seat This screw 44:

around the port hole 37 there will be no leakage and the air tensionwill rise in the player action and the control box 23 up to the maximumbeing created by the pneumatic pump'20.

As the 'movement of the spring 17 to change the pull on the valve 19 isvery slight and due to the action of the pneumatic pouch 15 in helpingto close this valve 19 at the highest, tension, there is no breakingdown of the'springfrom excessive stretching.

With this action of all parts being made to move only a short distanceand the ability to regulate this distance by only removing the mufl'ler10, the regulation can be adjusted to give the exact degree veryquickly, also the action of these parts when operatingis so fast thatthe t-ension can be raised to the desired degree almost instantly to.strike a melody note and yet'can drop back at once so asnot to raise thetension of the accompaniment notes.

Many modifications can be made, but what I claim'as my invention 1s:

1. In a mechanical musical instrument, a

pneumatic action, a power unit for creating a maximum degree of suctionto actuate the said pneumatic action; anexpression action comprising arelief valve, a port and a spring for controlling the suction of aircreated by the said power unit to a number of dilferent degrees, thesaid spring so connected as to be stiffened by a number of pneumaticsand separate means acting directly on saidrelief valve for closing offall ncomingair through HERSCHEL E. TOWER.

